/**
* @@@ START COPYRIGHT @@@

Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.

* @@@ END COPYRIGHT @@@
 */

package org.trafodion.rest.util;

import java.util.concurrent.TimeUnit;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class RetryCounter {
  private static final Log LOG = LogFactory.getLog(RetryCounter.class);
  private final int maxRetries;
  private int retriesRemaining;
  private final int retryIntervalMillis;
  private final TimeUnit timeUnit;

  public RetryCounter(int maxRetries, 
  int retryIntervalMillis, TimeUnit timeUnit) {
    this.maxRetries = maxRetries;
    this.retriesRemaining = maxRetries;
    this.retryIntervalMillis = retryIntervalMillis;
    this.timeUnit = timeUnit;
  }

  public int getMaxRetries() {
    return maxRetries;
  }

  /**
   * Sleep for a exponentially back off time
   * @throws InterruptedException
   */
  public void sleepUntilNextRetry() throws InterruptedException {
    int attempts = getAttemptTimes();
    long sleepTime = (long) (retryIntervalMillis * Math.pow(2, attempts));
    LOG.info("Sleeping " + sleepTime + "ms before retry #" + attempts + "...");
    timeUnit.sleep(sleepTime);
  }

  public boolean shouldRetry() {
    return retriesRemaining > 0;
  }

  public void useRetry() {
    retriesRemaining--;
  }
  
  public int getAttemptTimes() {
    return maxRetries-retriesRemaining+1;
  }
}
